Sinful Addiction
by StrangerThanFiction25
Summary: Ichigo Kurosaki, an Amur leopard, is saved one night by a panther, named Grimmjow Jeagerjaques. After that night they keep running into each other, leading Ichigo to become addicted the panther. But what happens when Aizen takes an interest in Ichigo? Will Aizen end up ruining the chances of the two ever getting together? GrimmIchi
1. Chapter 1: Arrogant Panthers

Keen amber eyes watched Aizen intently, looking for the perfect moment to attack. The Amur leopard was full of rage, seething to attack the man before him. Aizen was cold and calculating as he lifted the gun in his hands, aiming to kill. This time around Aizen had no intentions of letting the leopard go with his life. The leopard, also, had no intentions of letting the man before him live. So, the two danced a deadly tango around each other in the destroyed living room.

The room had once been luxurious and lavished with the best that money could buy, but now looked like a tornado had torn through here. The couches knocked over, tables splintered and overturned, lamps lying on their sides casting deadly shadows across the room, and pictures splintered and shredded. In all the room was destroyed.

"It's a shame that you refuse to be a good pet," Aizen said, his lips curling in disgust, "and that you're willing to forfeit your life for a worthless panther. I had such high hopes for you, Fifteen."

With the gun leveled and aimed to kill, Aizen pulled the trigger as the leopard leapt at him, claws extended and teeth bared. The only sound to be heard was the bang of the gun shot followed by a heavy thud.

...

**Two weeks earlier**

Ichigo missed their old home up in the mountains. He and Shiro had been forced to come live with their father's crazy brother, Kisuke Urahara, when their family had been murdered by humans. So, they now lived in Karakura Town, a noisy city compared to their home up in the mountains. Shifters had only made themselves known to humans two years ago, so there were still many revolts against Shifters yet, which was why their family was killed. The humans in the village had found out that they were shifters and had killed their family, while Ichigo and Shiro had been away hunting. Well, his adoptive family. Ichigo had been abandoned as a baby and Shiro's family had taken him in. Shiro was a snow leopard shifter, while Ichigo was an Amur leopard shifter. The Amur shifters are a dying breed, with only about fifty of them left in the world. Luckily for Amur shifters, Ichigo is submissive, which means that he can get pregnant. Unfortunately, he doesn't plan to help repopulate his breed.

It's been several months since they had moved here and Ichigo has heard about a group of shifters, called the Espada, that are revolting against laws segregating shifters and humans. Sōsuke Aizen, the man that had taken control after Yamamoto, had made these laws as soon as he had gained control. It was rumored that Aizen collected exotic shifters, but no one knew what he did with them. With the segregation laws in effect, the shifters had been regulated to one side of the town and the humans on the other side. Shifters were also treated inferior to humans in every way possible, for example if a shifter wasn't careful he could be sold as a pet.

Ichigo had been walking through the back alleys and hadn't noticed when he had accidently crossed onto the human's side of town, until a group of humans had cornered him. Cats hate to be trapped or cornered and are known to lash out on occasion for that reason, and Ichigo was no exception to this. Ichigo gripped the bags in his hand, prepared to use them as soon as an opening presented itself to him.

One of the more muscular humans stepped forwards, eyeing the gothic number fifteen on the inside of his wrist. "Don't you know it's dangerous for a shifter, such as yourself, to be on the wrong side of town, especially one as beautiful you?"

Ichigo snarled in warning as one of the humans took a step closer to him, but backed away at the sound of the vicious snarl.

"You do know what happens to those shifters that are caught on this side of town, don't you," the biggest human asked, taking another step closer.

As Ichigo was prepared to swing the grocery bags in his hands, a black panther landed in front of him, startling the humans for a brief second before they charged forwards. The panther was a blur of claws and teeth as it easily took down the humans surrounding them. One human had managed to get around the panther without the panther's notice, which Ichigo knocked out effectively with the bags of groceries in his hands. With the last human taken care of, the panther turned to take in the sight of the orange haired teen behind it.

"Grimmjow," a voice called, catching the panther's attention.

The panther shifted into a naked man with light blue hair and cyan eyes, before calling back, "Nnoitra, you slow bastard, you missed out on the fight."

"You asshole," Nnoitra snarled, finally coming into view. "I told you to leave some for me."

"You took too long," Grimmjow stated, before turning back to Ichigo.

Ichigo had been staring at the gothic six on Grimmjow's back, while the two had been talking. Now that Grimmjow was facing him, he couldn't look at the gothic six anymore.

Grimmjow looked the young shifter up and down, before asking, "Don't you know what happens to shifters that wander onto the human side of town, bitch?"

"Of course I know what happens," Ichigo snapped, angry at the other for calling him a bitch.

"You're pretty aggressive for a bitch," Grimmjow commented thoughtfully, enraging Ichigo even more.

Blinded by rage, Ichigo swings his bags full of groceries at the arrogant shifter, hitting him in the head, before storming home. Grimmjow laid on the ground, watching the aggressive submissive leave the alley in a huff. Nnoitra was cackling in glee at having watched Grimmjow have his ass handed to him by a submissive. Tonight definitely wasn't his night Grimmjow thought, as his head throbbed in agony. What the hell did that beta have in those bags?

Ichigo had stormed the whole way home muttering about arrogant, blue haired dominants. He even stormed up to his bedroom, without eating. Awhile later Shiro opened the door cautiously to see Ichigo asleep. Shiro snuck into the room and lay by his adoptive brother, shifting into a snow leopard so that he could cuddle closer, he fell asleep easily.

...

Ichigo woke up to the annoying sound of his alarm clock screaming at him. He groaned and tried to get up, only to find that a massive weight was holding him down. Opening his eyes, he saw Shiro's slumbering face inches from his own.

"Shiro," he yelled, attempting to wake his brother.

Shiro didn't move, besides twitching an ear. Ichigo sighed before stretching his neck, so that he could lick Shiro's nose. Shiro startled awake, glaring at Ichigo in annoyance as he jumped off the bed in a huff. He chuffed at his brother before he wandered out of the room to get ready for school. Finally able to get up, Ichigo turned off his alarm clock, before he also started getting ready. Ichigo was out the door in record time, with a piece of toast dangling from his lips. Shiro was walking along beside Ichigo, humming an off tune version of some song that Ichigo didn't know. Since Ichigo's eighteenth birthday was coming up, Shiro had decided to stick to him at all times. On a beta's eighteenth birthday, they start going into heat for the first time, which for Ichigo was only in a week.

"So, Ichi what happened last night that put you in such a bad mood," Shiro asked.

"I ran into an arrogant alpha," he mumbled around the piece of toast in his mouth.

"Did he try doing anything to you," Shiro asked, going into full blown big brother mode.

Ichigo sighed, regretting telling his brother the truth. "No, Shiro."

Ichigo's answer didn't really sooth his brother as he was already in big brother mode. Shiro believed that every dominant was after his little brother. So, when he got started there was no stopping him. In the end, Ichigo end up ignoring his brother the whole way to school and until class started. Hell, even between classes he still had to ignore Shiro. Today definitely wasn't Ichigo's day. And his day really spiraled downwards during his English class.

The English teacher, Ulquiorra Schiffer, was an emotionless man that didn't understand many things, namely emotion and references to the heart, which is weird considering that he's a teacher. It was also his first year teaching, too. There was, also, controversy among the female students about what he shifted into. Ulquiorra has never made it known what his animal counterpart is.

"Everyone open your books to page," Ulquiorra began, only to be interrupted as the classroom door banged open.

Through the door walked in the man from last night: Grimmjow. The blue haired man walked into the room, completely ignoring the classroom full of students, up to the monochromatic teacher at the front of the room. Ichigo sitting near the back of the room, kept his head down hoping that the dominant shifter didn't notice him.

"Nel forced me to bring you your lunch," Grimmjow said, holding out the bag containing the other man's lunch, "which you forgot."

Ulquiorra took the bag from Grimmjow, his expression remaining as blank as ever. "Now get out of my classroom."

Grimmjow flicked him off, before turning to leave the classroom, only to stop suddenly. He was sniffing the air curiously, before grin light his face up. Turning in Ichigo's direction, Ichigo could see a bruise coloring one of his cheeks.

"Hey, bitch," the older male said tauntingly. "I didn't think that I'd see you here."

Ichigo growled low in his throat, resisting the urge to attack the man before.

Ulquiorra stepped up next to Grimmjow, his hands stuffed in his pockets. "Grimmjow quit harassing my students," he said, his monotone voice never varying, "and get out of my classroom," he said, kicking the panther effortlessly out of the class room. "Now open your books to page twenty-one."

...

Ichigo walked out of the school by his self, Shiro had been forced to stay after school for detention. As he walked away from the school's main entrance, he didn't notice Grimmjow until he heard his voice.

"Hey, bitch," the arrogant voice of Grimmjow's came, grating on Ichigo's nerves. "You owe me for yesterday."

Ichigo swiveled on his heel to face the man behind him, his amber eyes snapping in fury. "What the hell do I owe you for?"

"For this," he said, jerking his thumb at the dark bruise on his cheek before stuffing his hand back in the pocket of his leather jacket. "You ruined my good looks."

"On the contrary, I think I fixed your face," Ichigo said, happy with his self. "And how the hell do you suggest that I pay you back for that?"

Grimmjow grinned, before gripping the back of Ichigo's head and slamming the younger's lips against his. Ichigo couldn't help but notice how soft Grimmjow's lips were, only to grow angry with his self and bite the blue haired man's bottom lip harshly, drawing blood. Grimmjow drew away from the younger, licking his bottom lip with a grin.

"I'm sure you'll think of something," he said, before jogging off towards the gleaming black and chrome motorcycle parked by the curb.

As Grimmjow speed away, Ichigo noticed a blue panther painted onto the side of motorcycle's gas tank. Growling, Ichigo made his way home in a bad mood again. For once he wished that Shiro had been with him. From now he definitely wasn't leaving school without Shiro.

* * *

**A/N: **Hola, readers. I've started another story as you can tell. What do you guys think? I'll be posting Spin Me a Fairytale and Dance with the Devil sometime during the next couple days. Reviews and all that good stuff greatly appreciated.

Ichigo: Great, now I'm able to get pregnant.  
Author: Your still kick ass, even though you can get preggo =)  
Ichigo: I hate you.  
Author: Your so mean to me, Ichi-berry DX


	2. Chapter 2: Can't Get Away From You

Ichigo kicked the side of the punching bag with his leg, taking out his anger on the inanimate object. Underneath the shop Kisuke owned was an underground training area that Ichigo took advantage of, which is exactly what Ichigo was doing right now. Pretending that the punching bag was Grimmjow definitely helped Ichigo relieve some of his anger. For a moment a memory of a time that Ichigo has no recollection of flashes in his mind.

A woman stood over his crib with blood dripping out of her mouth, as Ichigo watched her with wide eyes. She smiled softly down at him, as she used the sides of the crib to hold herself up.

"Ti amo," she whispered softly to him in Italian, "Ichigo."

Tears had begun to spill down her face as she brushed her hand through his short orange locks. Her arms had started to shake in her effort to keep herself upright. In the next second, her arms could no longer holder her up any longer and she crumpled to the ground.

As suddenly as the memory appeared it disappeared, leaving Ichigo confused and his head hurting. Swiping his hand out at the punching bag, the material ripped as his claws tore through it with ease. The sand poured to the ground like a waterfall, as Ichigo looked down at his hand with its claws extended. He hadn't realized he had released his claws. At the sound of someone coming down the stairs, Ichigo quickly sheathed his claws. Ichigo walked towards the stairs expecting to see Shiro, not Shinji walking down the stairs with a wide grin on his face. Shinji's teeth had always reminded Ichigo of piano keys.

"What are you doing here," Ichigo asked, not in the mood for company.

"What no warm welcome," Shinji frowned slightly, before his grin came back. "Hiyori and I are here, because Kisuke asked us to be. I guess it seems that some group of shifters is interested in using the training grounds here."

"Really," Ichigo mumbled more to himself than anyone else.

"Yep," Shinji stated cheerfully.

"Where's Hiyori," Ichigo asked, looking around for the volatile shifter.

"Hiyori's upstairs waiting with Kisuke," Shinji said.

Shinji opened his mouth to say something else, but was cut off by Hiyori hollering, "Shinji get your ass up here."

"Well that's my cue," Shinji piped, before running back up the stairs.

Curious as to whom this gang was, Ichigo followed Shinji up the stairs. Standing at the top of the stairs, Ichigo peered around the corner trying to catch a glimpse of the people in this group. He couldn't see anyone, but he did hear a voice besides Kisuke's that sounded awfully familiar. Until he caught a glimpse of blue hair, Ichigo hadn't been able to place who that voice belonged to. He couldn't believe how unlucky he was that he had run into that man again so soon. Snarling, Ichigo wandered back down the stairs into the training grounds. Taking the destroyed punching bag down, Ichigo was about to go throw it away when he heard people walking down the stairs. Shifting into an Amur leopard, Ichigo lay on the destroyed punching bag watching the group of people come down the stairs.

In the front of the group was Kisuke followed by Grimmjow, Shinji, Nnoitra, Hiyori, and an Amazon woman with blond hair. Kisuke was holding his fan in front of his face as he told the group about the underground training grounds. Grimmjow was listening to Kisuke as he took in the room. His cyan eyes swept the room taking in every detail, almost skipping over Ichigo's form curled up on the ruined punching bag. Staring at Ichigo curiously, Grimmjow continued listening to Kisuke without his eyes ever wavering from him. The slight flair of the blue haired man's nostrils was all that gave away that he was sniffing the air, trying to figure out who Ichigo was. Ichigo silently prayed that the other man wouldn't recognize him, since he had never seen his animal counterpart.

Once Kisuke was done talking, Grimmjow told him that he would use the place and even pay for his group to use it, which Kisuke surprisingly passed up on and let him use for free. Growling quietly to himself, Ichigo realized he had lost his place to relieve his stress to the arrogant dominant. Getting up from his spot on the floor, Ichigo decided that he would clean up the ruined punching bag later when Grimmjow was gone. Slinking away from the group, Ichigo silently made his way to the stairs only to stop at the feel of someone sniffing his fur. Raising the hackles on his neck, he quickly swiped his claws at the thing sniffing him. His amber eyes locked onto the culprit, as he bared his teeth and growled low in his throat. The culprit just so happened to be a panther, the one and only Grimmjow.

Grimmjow, who had leapt out of the range of Ichigo's swipe, padded closer to Ichigo as he smelt the Amur leopard again. Ichigo snarled as he struck out at the panther again with his claws. His ears flattened to his skull, Ichigo crouched to the ground prepared to attack again. Ichigo knew that even if the other didn't realize who he was, Grimmjow would still be able to smell that he was a submissive getting close to going into heat. And without a dominant around, the other could try and claim him, which Ichigo wasn't having any of that.

The door to the training area opened and the sound of Shiro's voice came down the stairway. "Hey Kisuke have you seen Ichigo?"

It didn't take a lot to know that Shiro had figured out where Ichigo was and that he was in big brother mode once again, as a vicious snarl rang throughout the training area. After the snarl had left the pale twin's lips, he had already shifted and was bounding down the stairs to Ichigo's rescue. Shiro landed in between Ichigo and Grimmjow ready to attack. With his sharp teeth bared at the dominant that had been getting too close to his baby brother for his liking, Shiro prepared to attack. Grimmjow realizing it was time to back off, even though the snow leopard was smaller than him, slowly backed away keeping a wary eye on the pissed off snow leopard.

With the panther far enough away and Shiro between them, Ichigo quickly climbed the stairs out of the training area and into the safety zone of his room. Shifting back into a human, Ichigo quickly got dressed and clambered into the middle of the bed. Ichigo didn't sit for long on the bed before Shiro padded into the room. Crossing the room with easy strides, Shiro jumped in the bed with Ichigo and pulled him against his chest.

"Didn't I tell you to stay away from dominants," Shiro asked.

"Yeah," Ichigo remarked. "And you also told to wait for you after school, which I also didn't do."

Shiro growled softly, already knowing that his twin hadn't listened to him there either. Sometimes Shiro wished Ichigo would listen more sometimes, but if he did than he wouldn't be the Ichigo that he loves.

"I should put a leash on you," Shiro grumbles to which Ichigo laughs, knowing that Shiro would never do that to him, before he begins to purr.

Having learned long ago how purring calmed his pale twin down, Ichigo purrs only to calm Shiro down, which happens to be a lot. Shiro sighs contentedly as he lays down on the bed by Ichigo, the effects of the other's purring already taking ahold of him. With Shiro lounging sleepy beside him, Ichigo pulled out his heaps of homework and set to work doing it. The homework was very time consuming and boring, but it had to be done unless he wanted to flunk school, which wouldn't help his chances at becoming a doctor at all. Glancing at his brother, he noted that Shiro had fallen asleep beside him. Feeling thirsty and a bit hungry, Ichigo quietly snuck out of the room so as not to disturb Shiro.

The kitchen was empty, when Ichigo wandered into the room to his relief. Getting his self a glass of water, Ichigo leaned his back against the counter as he took a drink. His head had begun to subtly start pounding from all the homework he had done tonight. It was a great relief to have all that homework out of the way, meaning he could go to bed after he was done down here. Ichigo was so zoned out that he didn't hear when some else had entered the kitchen.

"Hey, bitch," Grimmjow quipped.

Ichigo's eyes opened wide in shock as he spewed the water in his mouth across the room. He had completely forgotten that Grimmjow was here, even though he wasn't sure why he was still here yet at midnight.

"What are you still doing here," Ichigo sputtered.

"I thought that was you I smelt earlier, bitch," Grimmjow said, sauntering into the room.

* * *

**A/N: **I'm sorry it took me so long to update. I've just so much shit to do it wasn't even funny, it was almost impossible to write a sentence not even considering a chapter. But anyways, what do you guys think? Reviews and all that good stuff apperciated. Oh, and don't worry I'm slowly but surely working on my other stories, too.

Ichigo: ...  
Author: Ichigo's giving me the silent treatment for making him able to get pregnant. T^T


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